Heat dissipation device and method for manufacturing same

ABSTRACT

An exemplary heat dissipation device includes a base plate and heat pipes. The base plate defines recesses at one side surface and locating holes communicating with the recesses. The heat pipes each include an evaporating section received in a corresponding recess and a condensing section extending from the evaporating section. The evaporating section includes a bulge protruding outward from an outer surface thereof. The evaporating sections of the heat pipes are interference fitted in the recesses with the bulges protruding into the locating holes.

BACKGROUND

1. Technical Field

The disclosure generally relates to device cooling, and more particularly to a heat dissipation device including a base plate interferingly fitted with a heat pipe.

2. Description of Related Art

Heat dissipation devices are used to remove heat from heat-generating electronic components such as central processing units (CPUs) and others, keeping the electronic components within safe working temperature limits, and enabling stable operation. A typical heat dissipation device includes a base contacting an electronic component and absorbing heat therefrom, a number of fins, and a heat pipe. The heat pipe has one end connected to the base by solder and the other end connected to the fins. The fins dissipate the heat to the ambient environment.

When the heat dissipation device is manufactured, soldering flux must be added between the heat pipe and the base to provide for soldering between the heat pipe and the base. Furthermore, when the heat pipe and the base are made of different materials, a nickel-plating process may be required before soldering. Such process materials and manufacturing procedures render assembly of the heat dissipation device somewhat costly and complicated.

What is called for, then, is a heat dissipation device which can overcome the limitations described.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a heat dissipation device according to an exemplary embodiment of the present disclosure, wherein the heat dissipation device includes a base plate, a supporting frame, a number of heat pipes and a fin unit, with one fin of the fin unit shown exploded away for the purposes of clear illustration.

FIG. 2 is an isometric, bottom-up, assembled view of the heat dissipation device of FIG. 1.

FIG. 3 is similar to FIG. 1, but with the fin unit omitted.

FIG. 4 is an exploded view of FIG. 3.

FIG. 5 is an isometric, bottom-up view of the parts shown in FIG. 4.

FIG. 6 is a cross-section of the heat dissipation device of FIG. 2, taken along a line VI-VI thereof.

FIG. 7 is a cross-section of the heat dissipation device of FIG. 2, taken along a line VII-VII thereof.

FIG. 8 is a view corresponding to FIG. 6, schematically showing a number of rough heat pipes pre-assembled to the base plate and ready to be attached to the base plate via a punch mold, according to an exemplary method of the present disclosure for manufacturing the heat dissipation device of FIG. 1.

FIG. 9 is similar to FIG. 8, but showing the rough heat pipes after they have been attached to the base plate.

DETAILED DESCRIPTION

Reference will now be made to the figures to describe the present heat dissipation device and method in detail.

Referring to FIGS. 1 and 2, a heat dissipation device according to an exemplary embodiment of the present disclosure includes a base plate 10, a supporting frame 20, a fin unit 30 and four heat pipes 40. In alternative embodiments, the number of heat pipes 40 can vary according to particular requirements.

The fin unit 30 includes a plurality of fins 31 stacked one on the other in a vertical direction. Each of the fins 31 is a substantially rectangular thin metallic plate. The fins 31 are arrayed parallel to each other. Each of the fins 31 includes a substantially rectangular main body 310, and two flanges 312 respectively depending from front and rear sides of the main body 310. Four through holes 3102 are defined in each of two opposite lateral sides of each of the fins 31. The flanges 312 of each two neighboring fins 31 cooperatively define a planar front surface of the fin unit 30 and a planar rear surface of the fin unit 30, and regularly space the main bodies 310 of the fins 31 from each other. Thereby, a plurality of flow channels is defined between all the neighboring fins 31.

The supporting frame 20 is metal, and is configured for holding the heat pipes 40 in position. Referring to FIGS. 3-5 together, the supporting frame 20 includes a substantially rectangular mounting plate 21, two connecting plates 23 angling obliquely out from two opposite sides of the mounting plate 21, respectively, and two supporting plates 25 extending outward from peripheries of the connecting plates 23, respectively. Two mounting holes 212 are defined in front and rear ends of the mounting plate 21, respectively. Each of the supporting plates 25 defines four perforations 251 along a longitudinal axis thereof, the perforations 251 corresponding to four respective through holes 3102 of each fin 31. Two elastic arms (or spring fingers) 253 angle obliquely up from a top surface of each of the supporting plates 25. Each of the elastic arms 253 has a fixed end connected to the corresponding supporting plate 25, and a free end spaced from the corresponding supporting plate 25. In each of the supporting plates 25, the fixed ends of the elastic arms 253 are symmetrically opposite each other, and the free ends of the elastic arms 253 extend outward in opposite directions from the fixed ends, respectively.

Each of the heat pipes 40 is substantially U-shaped, and includes an evaporating section 41 and two condensing sections 45 extending upward from two opposite ends of the evaporating section 41, respectively. The condensing sections 45 of the heat pipes 40 have round cross-sections, with an outer diameter of each condensing section 45 slightly exceeding a diameter of each of the through holes 3102 of the fins 31. The evaporating sections 41 of the heat pipes 40 are flattened. Referring to FIGS. 6 and 7 together, the evaporating section 41 of each of the heat pipes 40 includes a planar top surface 411, a planar bottom surface 413, and two side surfaces 415 connected between two opposite sides of the top and bottom surfaces 411, 413, respectively. The top surface 411 is wider than the bottom surface 413. The evaporating section 41 has a substantially isosceles trapezoidal transverse cross-section, with a width gradually increasing from the bottom surface 413 towards the top surface 411. A bulge 412 protrudes upward from a middle portion of the top surface 411 of each of the evaporating sections 41. Two protuberances 414 protrude upward from two opposite ends of the top surface 411 of each evaporating section 41, respectively.

Referring back to FIGS. 3-5 together, the base plate 10 overall is H-shaped. The base plate 10 includes a rectangular heat absorption plate 12, and two extending plates 14 at front and rear ends of the heat absorption plate 12, respectively. The heat absorption plate 12 is connected between middle portions of the extending plates 14. Four recesses 123 are defined in a bottom surface of the heat absorption plate 12, for respectively receiving the evaporating sections 41 of the heat pipes 40 therein. Each of the recesses 123 extends parallel to a transverse axis of the heat absorption plate 12. A depth of each of the recesses 123 is substantially equal to a thickness of each of the evaporating sections 41.

Four locating holes 121 are defined in a top surface of the heat absorption plate 12, directly above the recesses 123, respectively. The locating holes 121 are equally spaced from each other along a longitudinal axis of the heat absorption plate 12. Each of the located holes 121 communicates with a corresponding recess 123. Each of the recesses 123 defines a substantially isosceles trapezoidal cross section. Each recess 123 is surrounded by an extended top wall 1231, and two sidewalls 1233 angling obliquely down from two opposite sides of the top wall 1231, respectively. A transverse width of each of the recesses 123 gradually decreases from the top wall 1231 downward. Two threaded holes 125 are defined in two opposite front and rear ends of the heat absorption plate 12, respectively. Each of the recesses 123 is shorter than the evaporating section 41 of each of the heat pipes 40.

Referring to FIGS. 8 and 9, aspects of an exemplary method for manufacturing the heat dissipation device are illustrated. The base plate 10 and four rough heat pipes 40 a are provided. Each rough heat pipe 40 a has an evaporating section 41 a with a round cross-section. A diameter of the evaporating section 41 a is substantially equal to a minimum width of each recess 123, and exceeds a height (or depth) of each recess 123. The evaporating sections 41 a of the rough heat pipes 40 a are received in the recesses 123 of the base plate 10, respectively, with a portion of the evaporating section 41 a of each rough heat pipe 40 a protruding above the corresponding recess 123 (as viewed in FIG. 8).

A punch mold 60 having a planar surface 61 facing the bottom surface of the heat absorption plate 12 is driven downward (as viewed in FIG. 8) until the planar surface 61 fully contacts the bottom surface of the heat absorption plate 12, and thereby the punch mold 60 deforms the evaporating sections 41 a of the rough heat pipes 40 a to match the recesses 123 of the base plate 10. In each of the rough heat pipes 40 a, a portion of an outer surface of the evaporating section 41 a forms the bottom surface 413 coplanar with the bottom surface of the heat absorption plate 12, another portion of the outer surface of the evaporating section 41 a forms the top surface 411 contacting the top wall 1231 within the corresponding recess 123, another portion of the outer surface of the evaporating section 41 a forms the bulge 412 fittingly received in the corresponding locating hole 121, and the other portions of the outer surface of the evaporating section 41 a form the two side surfaces 415 contacting the sidewalls 1233 within the corresponding recess 123. Thus, the heat pipes 40 are interference fitted into the recesses 123 and firmly connected to the base plate 10.

Referring back to FIG. 7, portions of the outer surface of the evaporating section 41 a of each of the rough heat pipes 40 a form two protuberances 414. The protuberances 414 are located adjacent to two opposite ends of the corresponding recess 123, and abut two opposite sides of the heat absorption plate 12, respectively. The protuberances 414 of each heat pipe 40 cooperatively limit relative movement between the heat pipe 40 and the heat absorption plate 12.

Referring back to FIG. 3, the supporting frame 20 is mounted to the base plate 10 via the condensing sections 45 of the heat pipes 40 being received through the perforations 251 of the supporting plates 25, respectively. The mounting plate 21 contacts the top surface of the heat absorption plate 12, with the mounting holes 212 aligned with the threaded holes 125 of the heat absorption plate 12, respectively. Two fasteners (such as screws) 50 extend downward through the mounting holes 212 of the mounting plate 21 and are engaged in the threaded holes 125 of the heat absorption plate 12, respectively, to connect the supporting frame 20 and the base plate 10. The supporting frame 20 can thus hold the heat pipes 40 in position.

The fin unit 30 is then provided and assembled to the heat pipes 40, via the condensing sections 45 of the heat pipes 40 interference fitting in the through holes 3102 of the fins 31. The elastic arms 253 of the supporting plates 25 of the supporting frame 20 elastically contact a bottommost fin 31 of the fin unit 30. The elastic arms 253 are deformed slightly to support the fin unit 30.

In the process of manufacturing the heat dissipation device, neither soldering flux nor nickel plating is required during assembly of the heat pipes 40 to the base plate 10. The manufacturing cost of the heat dissipation device is thus minimized, and the manufacturing of the heat dissipation device is simple and convenient.

It is to be understood, however, that even though numerous characteristics and advantages of the embodiments have been set forth in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. 

1. A heat dissipation device, comprising: a base plate defining at least one recess at one side surface thereof and at least one locating hole communicated with the at least one recess; and at least one heat pipe comprising an evaporating section received in the at least one recess and a condensing section extending from the evaporating section, the evaporating section comprising a bulge protruding outward from an outer surface thereof; wherein the evaporating section of the at least one heat pipe is interference fitted in the at least one recess with the bulge protruding into the at least one locating hole.
 2. The heat dissipation device of claim 1, wherein the at least one locating hole is defined at another side surface of the base plate which is opposite to the side surface having the at least one recess.
 3. The heat dissipation device of claim 1, wherein two protuberances protrude outward from the outer surface of the evaporating section of the at least one heat pipe in substantially the same direction as the bulge protrudes, and the protuberances abut two opposite sides of the base plate to limit relative movement between the at least one heat pipe and the base plate.
 4. The heat dissipation device of claim 1, wherein the evaporating section comprises a bottom surface coplanar with the one side surface of the base plate, a top surface wider than the bottom surface, and two side surfaces connected between two opposite sides of the top and bottom surfaces.
 5. The heat dissipation device of claim 4, wherein the evaporating section has a substantially isosceles trapezoid cross-section.
 6. The heat dissipation device of claim 4, wherein the bulge is formed on the top surface of the evaporating section.
 7. The heat dissipation device of claim 1, further comprising a fin unit, wherein the fin unit comprises a plurality of fins each defining a through hole, and the condensing section of the at least one heat pipe is interference fitted in the through holes of the fins.
 8. The heat dissipation device of claim 7, further comprising a supporting frame between the fin unit and the base plate, the supporting frame comprising a mounting plate connected to the base plate, a plurality of connecting plates extending obliquely from the mounting plate, and a plurality of supporting plates extending outward from the connecting plates, respectively, the supporting plates contacting a bottommost fin of the fin unit.
 9. The heat dissipation device of claim 8, wherein a plurality of elastic arms extend upward and obliquely from the supporting plates, each of the elastic arms having one end extending from a corresponding supporting plate and another end spaced apart from the corresponding supporting plate, the elastic arms elastically contacting a bottommost fin of the fin unit.
 10. The heat dissipation device of claim 8, wherein the at least one heat pipe further comprises another condensing section, the condensing sections extending from two opposite ends of the evaporating section of the at least one heat pipe, respectively, the supporting plates defining perforations, and the condensing sections of the at least one heat pipe extending through the perforations.
 11. A method for manufacturing a heat dissipation device, the method comprising: providing a base plate defining at least one recess at one side surface thereof and at least one locating hole communicated with the at least one recess; providing at least one heat pipe comprising an evaporating section and a condensing section extending from the evaporating section, the evaporating section having a round cross-section, a diameter of the evaporating section larger than a depth of the at least one recess; mounting the at least one heat pipe to the base plate with the evaporating section received in the at least one recess, a portion of the evaporating section protruding from the at least one recess; and punching the at least one heat pipe to force the evaporating section to deform and interferingly fit in the at least one recess, wherein a portion of an outer surface of the evaporating section forms a bulge protruded into the at least one locating hole, to thus connect the at least one heat pipe and the base plate together.
 12. The method of claim 11, wherein the at least one recess has a substantially isosceles trapezoid cross-section.
 13. The method of claim 11, wherein the at least one recess is surrounded by a top wall and two sidewalls extending obliquely from two opposite sides of the top wall, a width of the at least one recess decreasing from the top wall.
 14. The method of claim 13, wherein after punching the at least one heat pipe, a portion of the outer surface of the evaporating section forms a bottom surface coplanar with the one side surface of the base plate, a portion of outer surface of the evaporating section forms a top surface abutting the top wall, and the other portion of the outer surface of the evaporating section forms two side surfaces abutting the sidewalls, respectively.
 15. The method of claim 14, wherein the bulge is formed on the top surface.
 16. The method of claim 11, wherein after punching the at least one heat pipe, a portion of the outer surface, which is adjacent to two opposite ends of the at least one recess, of evaporating section forms two protuberances protruding in substantially the same direction as the bulge protrudes, and the protuberances abutting two opposite sides of the base plate to limit relative movement between the at least one heat pipe and the base plate.
 17. The method of claim 11, wherein the at least one locating hole is defined at another side surface of the base plate which is opposite to the side surface having the at least one recess.
 18. The method of claim 11, further comprising providing a supporting frame which comprises a mounting plate connected to the base plate, a plurality of connecting plates extending obliquely from the mounting plate, and a plurality of supporting plates extending outward from the connecting plates, respectively, the supporting plates defining perforation for the condensing section of the at least one heat pipe extending therethrough.
 19. The method of claim 18, further comprising providing a fin unit which comprises a plurality of fins, each of the fins defining at least one through hole, and the condensing section of the at least one heat pipe being interference fitted in therein.
 20. The method of claim 19, wherein a plurality of elastic arms extend upward and obliquely from the supporting plates, each of the elastic arms having one end extending from a corresponding supporting plate and another end spaced apart from the corresponding supporting plate, the elastic arms elastically contacting a bottommost fin of the fin unit. 